<html>
<head>
<style>
span#dd:before {
  display: inline;  white-space: pre;  content: "bef-\Aore";
  color: gray;}
</style>
<script>
function boo()
{
  var div = document.getElementById("div"); 
  var dd = document.getElementById("dd");
  var newTextNode = document.createTextNode("new");
  dd.insertBefore(newTextNode, div);
}

window.addEventListener("load", boo, false);

</script>
</head>
<body>
<span id="dd"><div id="div">div</div></span>
</body>
</html>
